USB 3 is not backwards compatible with audio.
I bought a Sony Pro 11 only USB 3 ports, when it was released, to find out that all my USB dacs did not work. Ended up having to buy a Sony T Ultrabook as well, which has one USB 2. This is extremely annoying to say the least.
There is no way around it on the Sony Pro 11, took it to some savvy tech guys and they could not get music files to play.
I thought with Macs, it was fine?!?!
Strange, I have my Vega running off USB 3 with my Adnaco card thing.